Air volume control



ug- 7, 1945' BRANDsTRoM 2,381,640

AIR VOLUME CONTROL Filed Feb. 24, 1945 5 Sheets-Sheet l Aug. 7, 1945. F. BRANDSTROM 2,381,640

AIR VOLUME CONTROL Filed Feb. 24, 1945 3 sheets-sheet 2 www Y if', IIIA? Aug. 7, 1945.

AIR VOLUME CONTROL Filed Feb. 24, 1943 .if l ff jf' /f F. BRANDsTRoM 3 Sheets-Sheet 3 f. Y y

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Patented Aug. 7, 1945 AIB VOLUME CONTROL Fred Brandstroni, Westport, Conn., assignor to Manning, Maxwell Moore, Incorporated,` New York, N. Y., a corporation of New Jersey Application February 24, 1943, Serial No. 476,941

I 4 Claims.

This invention pertains to liquid storage systems of the kind in which the liquid isintermittently delivered to an air-tight tank or reservoir by a pump or the like and is kept under resilient pressure by a body of gas entrapped within the reservoir above the liquid. A domestic water supply system comprising an air-tight tank or reservoir of moderate capacity is hereinafter specincally referred to as exemplifying one field of utility for the present invention which vmore particularly relates to an automatic air volume ccntroller for use in such a system.

It is essential, for emcient service and greatest economy, that the volume of air maintained within the tank be such as entirely to illl the tank at such pressure as just about to balance a column of water oi' a height equivalent'v to the distance between the bottom of the tank and the lowest discharge outlet on the service pipe of the system. thus making it possible to draw out all of the water which is pumped into the tank from any 'part of the service piping connected to the tank.

This requirement makes necessary the introduction of air additional in volume to and under higher pressure than that naturally illling the tank at atmospheric pressure.

Various methods of introducing into the tank the additional amount of air required (over that which will enter naturally and at atmospheric pressure) have been suggested previously; among them the admission of air in small regulated amounts into the suction pipe of the water pump through a suitable control valve-the air being drawn in by the partial rvacuum in the suction pipe and carried with the water through the pump delivery pipe into the tank; and the provision of a power actuated air pump or compressor designed to deliver air under pressure directly into the tank and whose operation is independent of pressure conditions in the intake of the water pump. It

is plain that by such prior methods of introducing air the relative volumes of air and pressure are quite likely to become disproportioned due not only to tank leakage and .absorption of air by the water but also to the unregulated supply of air which may be introduced.

Among the objects of the invention are to provide a simple, cheap and easily manufactured air volume controller useful in systems of the above typein particular to provide a controller whose constituent parts may in most instances be made rapidly and cheaply by automatic'machinery of commercial type and to such dimensional4 tolerances as to make them interchangeable; to provide air volume control for use with either of the above mentioned types oi' air supply; to provide an air volume controller of small dimensions and whose installation in a completed tank or reservoir necessitates merely the provision of a single comparatively small tapped hole in the wall of the tank; and further to provide an air volume controller having provision for so associating with it a pressure gauge that the single opening in the tank wail above referred to sufiices for the entire assembly.

- Other and further objects and advantages of the invention will be pointed out hereinafter in the following more detailed description and by reference to the accompanying drawings, wherein Fig. 1 is a diagram illustrating the present invention as used in a domestic water supply system; v

Fig. 2 is an elevation, to larger scale, illustrating the air pressure control device of the present invention;

Fig. 3 is a view generally similar to Fig. 2, but to larger scale and with certain parts broken away and others invertical section, showing the device installed in the wall of a tank or reservoir;

Fig. 4 is an end elevation of the device shown in Fig. 3;

Fig. 5 is a diametrical vertical section through the supporting plug upon which the other parts of the control device are mounted;

Fig. 5'- is a front elevation of the plug ofFig. 5;

Fig. 6 is a fragmentary elevation of the iioatsupporting rod showing the pressure sealing diaphragm mounted thereon;

Fig. 7 is a diametrical section, to larger scale, showing, in detail, the mode of securing the iloat rod to its supporting diaphragm:

Fig. 8 is an elevation of a guide plate designed to guide the float rod as it moves up and down;

Fig. 9 is a diametrical section, to large scale, of the airlinlet plug;

Fig. l0 is a view generally similar to Fig. l but illustrating the invention as embodied in a,.sys tem comprising a power driven air compressor for delivering air to the storage tank;

Fig. 11 is a view similar to Fig. 5, but illustrate ing a control device useful in the system of Fig. 10;

Fig. 12 is a view similar to Fig. 11, but showing a further modification wherein provision is made for maintaining, at certain times, a predetermined pressure within the storage tank;

Fig. 13 is a view similar to Fig. 12but showing a slight modification of the structure illustrated in the latter figure;

Fig. 14 is a vertical, diametrical section through the supporting plug forming a part of the devices shown in Figs. 11, l2 and 13, but with the moving parts removed:

Fig. is a vertical diametrical section showing a valve seat arrangement used in the device of Fig. 11; and

Fig. 16 is a side elevation of a valve employed in the device of Figs. 11, 12 and 13.

Referring to the drawings, the numeral I (Fig. 1) designates the improved air pressure control device of the present invention as a whole, such device being shown as mounted at the upper part of the side wall of an air-tight water reservoir 2. This reservoir is supplied with water by means of a pump 3 of any suitable type driven by an electric motor 4 and delivering water through the pipe l into the upper part of the tank 2. Tile pump is provided with a suction pipe t from which extends the branch pipe 'l which communicates with the air inlet of Ithe pressure control device i. The motor is supplied with current from the power line L, the motor being in series with the Pressure control device I so that the switch forming a constituent part of the latter determines the starting and stopping of the motor.

Referring to Fig. 3 the improved control device oi the present invention comprises a support 8 in the form of a plug having a pipe thread at l by means of which it may be screwed into a threaded aperture in the wall'2'I of the tank 2.

'I'his plug is provided with an eccentrically located bore I Il leading inwardly from its outer end, and this bore is internally screw threaded to receive a threaded nipple I I projecting from and constituting supporting means for a pressureactuated electrical switch I2, here illustrated as housed in the same easing with a pressure gauge. This switch may be of any appropriate type comprising pressure-actuated motor means such, i'or example, as a diaphragm which in moving in one direction closes switch contacts, and when moving in the other direction separates the contacts. 'I'his switch as above suggested is connected in series with the motor 4 and thus determines the operation of the pump 2. A passage I3 extends from the inner end oi' the bore It tothe inner end of the plus l. thus providing i'ree communication between lthe interior oi' the tank and the sauge and the pressure motor of the switch.

The plug i is furnished with an axial bore I4 (Figs. 5 and 5*) leading inwardly from its inner end, such bore having an internally screwthreaded inner portion I 5 beyond which the bore is continued .to form a chamber I I oi' smaller diameter than the main portion Il oi' the bore, and this chamber Il has a further extension I1 of still smaller diameter which intersects a vertical bore I2 extending inwardly from the` periphery of the plug, and which is screw threaded at Il at its outer portion.

'Iliis bore Il receives an air control valve device 2l (Fig. 9) comprising a tubular portion 2l* designed to enter the bore Il and having partial threads A2li' which may be engaged with the threads at Il thereby to secure the valve device in assembled relation with the plug i. This valve Adevice also comprises .the externally threaded nipple portion 2| which is connected to the pipe 1, leading to the suction side of the pump, by means of a suitable coupling 22. A passage 23 extends from the interior of the tubular nipple 2I and connects with a longitudinal groove 24 extending to the upper end of the part 2I, thus providing communication between the chamber I1 and the pipe 1.

Another passage 21 extends inwardly through the member 2O to provide an air inlet leading to the axial bore 20 o! the part 2l.. Within this bore 20 is arranged a standard pneumatic tire valve 2l (Fig. 3) which has screw-threaded engagement with the upper part' of the bore 22 and which is provided with an upwardly projecting stem 3| located in the chamber I1. By depressing the stem 3| the valve is unseated thus providing communication between the inlet passage 21 and the chamber I1.

The valve-actuating means comprises the elongate iioat-supporting stem 22 of rigid material having the hollow iloat 3l secured to its righthand portion, as viewed in Fig. 3, and having its left-hand end I2 arranged to overlie the upper end of the valve stem II. The iloat I2 preferably comprises two opposed -hollow shells I4 and 2l* (Fig. 6), respectively, each having a cylin-= drical body portion and a spherically curved end. said shells being overlapped at l! and permanently secured at this point by solder. The rod I2 passes through an opening at Il in the closed end of the shell 24 and its right-hand end 22 may be seated in a socket at Il in the closed end of the shell 24, Ithe rod 22 being secured at the points 36 and 31 by means of solder to the respective shells.

Near the left-hand end of the rod I2 a sleeve Il (Fig. '1) is secured to the rod by means of solder, said sleeve having a radial flange 3l which forms a rigid support for one face of a flexible diaphragm I0 of suitable material, for example rubber, rubberized textile fabric, flexible metal, or .the like. A washer 4I bears against the opposite surface of this diaphragm, and the lefthand end I2 of the sleeve 28, as viewed in Fig. 7, is peened over against the outer face of the washer to hold the parts in assembled relation. The diag phragm 4l is of s. diameter greater than that of the chamber I l in the plug l, and is designed to rest against the shoulder l2 at the inner end oi' the threaded portion Il of the bore Il. ari-,- nular nut 4l embraces the rod 22 and is designed to be screwed into the threaded portion Il of the bore Il and against the right-hand face oi' the diaphragm I0, thereby -to compress the latter and hold it in leak-tight contact with the shoulder 4I, usI providing a leak-tight closure for the cham- In order to guide the float in its vertical up and down movements a guide plate Il is providecLat the right-hand end of the plug. I. This guide plate (las. a) is s thin piece or rigid material, for example metal, and is secured to the end oi' the plug l by screws passing through openings Il inthe guide plate and into threaded openings 41 (ng. 5o in the ena of the plus.A 'rms nime plate is nunished with a vertically elongate slot Il through which theiioat rod 32 passes, the dimensions of the slot being such as to permit vertical movement of the rod, but substantially to prevent horizontal movement of the rod. The

fromthepositioninidicatedin ly, thus depressing the valve stem 3| and unseating the air valve 23. 'I'his provides communication between the air inlet 21 and the chamber I1. This chamber I1 is now in free communication with the suction o! the pump and as the pump continues to operate, air is drawn into the suction pipe 6 and delivered with the water into the tank thus rapidly building up pressure. When the pressure has risen to a predeternnned point, the pressure switch acts to stop the pump. When the water level inthe tank again drops suillciently to permit the float to drop, the valve stem 3| is released, thus allowing valve 29 to close. When the pressure drops suiliciently, the pump is started, thus delivering water to the tank. and when the water level has been raised so as to lift the iloat, air is again drawn, in, thus completing the cycle, and always insuring the maintenance of a suilicient body oi.' air above the water to provide the desired delivery pressure. 4

Referring to Fig. 10 the parts bearing the same reference numerals correspond to similarly designated parts in Fig. 1, but the controlling device I of Fig. 1 is replaced by the modiiied controlling device I'L now about to be described. In F18. 10 the pipe 1 of Fig. 1 is omitted and the motor 4 is arranged to drive both the pump 3 and an air compressor 'la which delivers air under a definite predetermined superatmospheric pressure into the upper part of the tank 2.

The controlling device I'L may in general be similar to the controlling device I above described, comprising a float-actuated valve mechanism and a combined gauge and pressure-actuated switch. This mechanism is carried by a support Il` (Figs. 11 and 14) having a screwthreaded portion 3 designed to enter a suitable screw-threaded aperture in the wall oi' the tank. 'Ihis support 88L is furnished with the eccentric internally screw-threaded bore III leading in from its outer end I, said bore being designed to receive the supporting nipple o! the combined gauge and pressure switch and communicating, by means of a passage I3, with the interior of the tank. T'he support also has the axial bore I4 having the screw-threaded portion I5; a portion I6 of reduced diameter; and the inner portion or chamber I1 which in this instance communicates by means of a passage I1` with the inner end of the bore III. The support also has the downwardly extending bore I3 communicating at its upper end of the chamber I1 and having an enlarged internally screw-threaded outer portion I3. The iloat 33 and the oatrod 32 are supported by the diaphragm 43 in the same way as above described. 'I'he inner end 32h of the oat rod is located in the chamber I1. V

In this instance the screw-threaded portion I3 of the bore I3 receives the seat-supporting plug 50 (Figs. 11 and'V 15)@having a longitudinal bore I and being provided at its upper or inner end with an annular seat 52 which may be of any suitable material, for example rubber or ber. With this seat cooperates a valve 54. This valve preferably has a polygonal body portion, for example it may be hexagonal, while its lower end 53 is conical and designed to cooperate with the seat 52 to close the passage 5I. The valve Il has a stem 5i which is provided with an opening 56, Fig. 16, which loosely receives the inner end 32h of the oat rod 32. 'I'he polygonal portion of the valve constitutes a guide for contact with the wall of the bore I3. although its nattened surfaces provide communication between the chamber I1 and the region Just above the valve seat I2. When the float is below the horizontal position the valve M is unseated .and thus pressure fluid is free to escape from the tank through the passage I3, the inner end of the bore I0, the passage I1, the chamber I1, thebore I3, and the passage 5I.A On the other hand, when the iloat rises above the horizontal, the valve 54 is pressed down against the seat 52 thus preventing further escape of pressure fluid.

With this arrangement and assuming that the water level in the tank has dropped to a point such that thestem of float 33 is below the horizontal and further assuming that the pressure in the tank has dropped low enough to close the switch contacts, the motor 4 is started thus concomitantly actuating the pump 3 and the air compressor 1*. Water and air are thus delivered into the tank 2. but since the valve 54 is unseated the air which enters the tank will be free to escape so that no substantial increase in pressure will occur within the tank. However, when e the water level has risen suniciently to cause the float 33 to become horizontal, the .valve 54 will be seated and as the pump and compressor continue to operate the water level in the tank will risa and the air pressure above the water will increase at a rate greater than that which would result lmerely from the rise in level i'rom the water. When the pressure in the tank has reached a predetermined amount the switch contacts will be opened automatically and the motor will stop. If desired, a check valve 1 may be arranged in the conduit leading from the pump and compressor to prevent leakage of pressure fluid out of the tank when the motor stops.

In some systems it is undesirable to permit the pressure in the tank ever to drop as low as atmospheric pressure and to insure this desired condition the arrangements illustrated in'Figs. 12 or 13 may be employed. Thus in Fig. 12, while the other parts are in general like those just above described, the seat supporting plug 50 o! Fig. 11 is replaced by the seat supporting plug 51 (Fig. 12). This plug is provided with an axial bore somewhat larger in diameter than the bore 5I of the plus 50 and within this bore is located a iispring-loaded relief valve lia-preferably fa valve of the type commonly employed in pneumatic tires. This valve is loaded by means of a spring 53 whose tension may be adjusted by the manufacturer, for example by means of a screw 60. Normally this valve 58 is closed, thus preventing escape of pressure uid from the tank. Thus, when as above described, the float is below the horizontal and valve 54 is unseated, air can escape from the tank only so long as the pressure in thetank is suicient .to overcome spring 59 and unseat valve 53. When the pressure in the tank drops to a predetermined point, valve 53 automatically seats, thus preventing further reduction in pressure.

In the arrangement shown in Fig. 12 the parts are generally similar to those shown in Fig. 11 except that the tensioning spring which controls the automatic relie! valve I3 is easily adjustable from outside of the device by means of a screw 30* having a knurled head 62 which is readily accessible for adjustment by the operator.

I claim:

1. In combination an air tight tank and a control unit comprising a support having an externally screw-threaded plugv portion designed to enter a screw-threaded opening in the tank wall.

ternally screw-threaded bore extending into it from its outer end and designed to receive a threaded supporting nipple forming part oi a:

pressure switch, the support having a longitudinal passage leading from the inner end of said eccentric bore to the inner end oi the plug thereby providing communication between the interior f of the tank and a pressure switch mounted on the support, the support lhaving axial bore extending inwardly from its inner end, and having a valve-receiving bore extending inwardly from its peripheral surface and intersecting the axial bore, a tire type valve having a protruding stem located in the valve-receiving bore and means for actuating the tire type valve comprising a iloat within the tank, the iioat having an elongate stem, a diaphragm extending transversely across said axial bore and forming one wall of an interior chamber constituted by the inner end of said axial bore, the oat stem extending leaktight through the diaphragm and the inner portion of the iloat stem overlying the end of the stem of the tire type valve for actuating the latter valve, means providing passages connecting said interior chamber with the interior of the tank and with the outer atmosphere respectively, the tire type valve being arranged to control the flow of air through the latter passage, and guide means operative to constrain the float stem to move in the plane of the axis oi the tire type valve.

2. In combination with an air-tight tank and a motor driven pump operative to deliver liquid and air into the tank, a control unit including a support having an externally screw-threaded plug portion for insertion in a threaded opening in the tank wal1,the support having a valvereceiving bore extending inwardly from its peripheral surface and which intersects an axial bore extending inwardly from the inner end of the support, `a valve housing within the valvereceiving bore, said housing having air inlet and delivery passages, a conduit connecting the delivery passage with the suction side of the pump, a tire-type valve which controls communication between the inlet and delivery passages, and a iloat within the tank mounted upon the support and having a stem whichl extends along the s,ssi,es o

said support having an eccentrically located in-A axisi bore and which is arranged to actuate the valve.

3. In combination in a liquid storage system of the sind in which liquid is miermiiniiy delivered to an air-tight tank by means oi' a pump and is kept under pressure by a body of gas entrapped above the liquid, alas volume controller comprising a support having an externally screw-l threaded portion designed to engage a threaded opening in the wall of the tank, the support having an interior chamber which 'always ccmmunicates with the suction side ot the pump and having an inlet passage leading to sa`id chamber from a source o! gas, a gas inlet valve controlling the ilow of gas through said passage, and a float within the tank, the iioat having a stem which' for the iloat and its stem, that portion o! the stem which is within the chamber being arranged to actuate the gas inlet valve.

4. In combination, in a liquid storage system of the kind in which liquid and air are intermittently delivered into an air-tight tank by motor driven means, and in which a pressureactuated switch, responsive to pressure variations in the tank, controls the operation of the motor,

air volume controlling means comprising a con- 80 trol unit including a support having an externally screw-threaded plug portion for insertion in a threaded opening in the tank wall. the support being provided with means for mounting the motor controlling switch thereon, and having therein an interior chamber provided with having a valve seat and an air inlet valve cooperable therewith to control the flow of air through a passage in the valve device extending between said interior chamber and the outer at-y mosphere, means providing communication between said interior chamber and the interior of the tank, a iioat within the tank, and motiontransmitting means passing leak-tight through the flexible wall of the chamber and operative o to transmit motion from the oat to the slr valve.

FRED BRANTRM. 

